Method of preparation of carbon transfer inks



United States Patent 3,214,282 METHOD OF PREPARATION OF CARBON TRANSFERINKS Hansel L. McGee, New York, and Paul M. Schwartz, Mahopac, N.Y.,assignors to International Business Machines Corporation, New York,N.Y., a corporation of New York No Drawing. Original application Dec.26, 1961, Ser. No. 162,280. Divided and this application May 2, 1963,Ser. No. 277,430

2 Claims. (Cl. 106-31) This application is a divisional application ofapplication Serial No. 162,280, filed December 26, 1961, entitledSynthetic Wax and Method of Preparation.

This invention relates to new chemical compounds having wax-likecharacteristics and to processes for preparing the same. This inventionfurther relates to a new amidoester synthetic wax which has all thevaluable characteristcis of natural waxes and, in addition, certaindesirable properties peculiar to itself.

Natural waxes such as montan, ouricury and carnauba wax, in which theessential molecular structure is the same, have found many applicationsin the field of coatings due to their film forming and polishingcharacteristics. These natural waxes and carnauba wax in particularproduce a very hard, durable, non-smearing lustrous film. In addition,because of unique properties, montan, ouricury and carnauba waxes havebeen found to be especially satisfactory as a major ingredient of carbontransfer inks of the hot melt type, such as are employed in themanufacture of carbon paper.

The excellent properties of the natural waxes, for example, carnauba waxand montan wax, are to some extent offset by certain disadvantages. Inparticular, the natural waxes are not always uniform in composition. Thenatural waxes vary in composition due to the different techniques ofpurification and refining, or they may have been adulterated with lesdesirable waxes, such as parafiin wax. Thus it is highly desirable toobtain a synthetic wax which is not subject to variations,uncontrollable or otherwise, which would render the natural waxunsuitable for various applications.

These synthetic waxes not only exhibit utility as waxes themselves, butalso as additives to carbon transfer ink formulations, automobile pasteand liquid polishes and as synthetic lubricants. These synthetic waxescan replace or fortify natural waxes, for example, montan, ouricury andcarnauba wax, when used in the above suggested applications. They canalso be used as plasticizers.

The synthetic waxes of the present invention provide a material ofdependable and predictable composition and properties which can be usedin the formulation of carbon transfer inks, automobile paste and liquidpolishes,

etc.

The principal object of the invention is to produce from staple rawmaterials a synthetic wax which can be manufactured under convenientcommercial conditions and at a moderate cost.

An object of the present invention is to provide a class of compoundshaving desirable wax-like properties and which are useful as substitutesfor natural waxes.

Another object of the present invention is the preparation of compoundswhich have properties comparable to those of natural waxes bothconsidered alone and when formulated into polishing compositions, carbontransfer inks, etc.

A further object of the invention is to provide synthetic waxes in placeof the natural Waxes used theerin and Another object of the invention isto provide synthetic waxes of dependable properties, composition,purity, etc., which are capable of replacing, without sacrifice of de-3,214,282 Patented Oct. 26, 1965 Ri-O-ii-Jir--OH wherein R is an alkylradical having from 16-22 carbon atoms, and wherein R is an alkyleneradical having from 2-8 carbon atoms and an amine of the generalformula: I s H-NR4 wherein R and R are selected from the groupconsisting of hydrogen and an alkyl radical having from 1-22 carbonatoms. These amido-esters have the following general formula:

ofltg R1Og-Rz( J -NR In the above formula, R is an alkyl radical havingfrom 16-22 carbon atoms, R is an alkylene radical having from 2-8 carbonatoms and R and R 4 are selected from the group consisting of hydrogenand an alkyl radical having from 1-22 carbon atoms.

The acid ester R1-O( iRzi lOH is prepared as set forth in the copendingUS. patent application S.N. 81,273 by Callinan et al. filed January 9,1961, entiled Substitutes for Carnauba Wax and Transfer Ink CompositionsContaining Such Substitutes. This copending application is herewithincorporated by reference. The process of preparation is as follows:Equal moles of the desired acid anhydride and alcohol were mixed in aflask fitted with a reflux condenser. A five fold excess of toluene(based on the weight of alcohol) was added as a solvent. The mixture wasthen refluxed until the reaction had gone to completion (approximately 5hours). The solvent was then removed in vacuo, and the residuecrystallized in a suitable solvent. Thus, the acid ester is now formedand ready to be used in the preparation of the amide-ester syntheticwax.

The amido-ester synthetic wax may be prepared in several ways. The acidesters,

R10-gRz( i-OH are converted to the acyl chlorides by reacting 1 mole ofthe acid ester with an appropriate amount of an acyl chloride formingreagent. The acyl chloride forming reagents which may be used arephosphorus pentachloride, thionyl chloride, sulfuryl chloride, andphosphorus trichloride, etc.

If thionyl chloride is used as the acyl chloride forming reagent,approximately 1 mole of the acid ester is mixed with 2 moles of thethionyl chloride. The mixture which results is heated to a temperatureof 30'-40 C. and allowed to reflux for 20 hours. The excess thionylchloride is removed by distilling at low pressure (for example, 1 mm.Hg). The solid residue which remains is the 3 crude acyl chloride of thecorresponding acid ester. (Yield is 70% of theoretical.)

Alternately, phosphorus pentachloride can be used as the acyl formingchloride reagent. In this case, a suspension of the acid ester (1 mole)in anhydrous ethyl other is cooled to 10 C. and 1.2 moles of phosphoruspentachloride is added thereto. The mixture is stirred for two hours atthat temperature, after which time the reaction mixture is filtered andwashed with anhydrous ethyl ether. The crude acyl chloride of thecorresponding acid ester remains. (Yield is 90% of the theoretical.)

Now the acyl chloride of the corresponding half ester is reacted with anamine l a (HNR4) If R and R are both hydrogen (NI-I then anunsubstituted amido-ester synthetic wax results it t t (R10CR -CNH) Ifone or both of R and R are an alkyl radical having from 122 carbonatoms, then a substituted amido-ester synthetic wax results (6 III(Rr--O--%R2GN-R4) u u (RrOC-R2CNR4) The crude amido-ester so obtainedmay then be purified by recrystallization from suitable solvents or bydistillation in vacuo.

The amine Illa (HN-R4) reactants utilizable herein are NH or primary orsecondary amines. The primary or secondary amines are preferably thosemonoor di-alkylamines having up to 22 carbon atoms per alkyl radical.The alkyl radicals may be straight chain or branched chain. The twoalkyl radicals in the secondary amine reactant may be the same or theymay be different, i.e. a combination of branched and straight chainsand/or radicals of different chain lengths. Illustrative examples ofprimary and secondary amines that may be used in carrying out the methodillustrated in the present invention are:

Methylamine Dibu-tylamine (monomet'nylamine) Amylamine DimethylamineOctylamine Ethylamine Decylamine Diethylamine Octadecylamine PropylamineMethylethylamine Isopropylamine Docosylamine DipropylamineDidocosylamine Diisopropylamine Methylbutylamine ButylamineMethylpropylamine Isobutylamine Ethylpropylamine Sec-butylamineEthylbutylamine An unsubstituted amido-ester synthetic wax may beprepared as follows:

1 mole of the acyl chloride of the corresponding acid ester is slowlyadded with stirring to 1 liter of concentrated ammonium hydroxide (thiscompound is used as a source of NH which has been cooled in an ice-saltbath to C. After all of the acyl chloride of the acid ester has beenadded, the mixture is stirred for one hour. The reaction mixture is thenfiltered and the residue is washed with Water. After drying in a vacuumoven at a temperature of 50 C. for 4 hours, the crude unsubstitutedamide-ester synthetic wax is recrystallized from a suitable hot solvent,such as for example ethanol.

A substituted amide-ester acid synthetic wax may be prepared in thefollowing manner:

1 mole of the acyl chloride of the corresponding acid ester is added toa solution containing 1 mole of an alkylamine and 1.1 moles of triethylamine. The mixture is stirred for 3 hours while cooling to 10 C. in anicesalt bath. The reaction product precipitates as it is formed and isfiltered, washed with Water and dried. The substituted amido-estersynthetic wax is purified by recrystallizing from hot chloroform or hottetrahydrofuran. (Yields are about 70%-80% of the theoretical.)

An alternate method of preparing substituted amidoesters involves theuse of dicyclohexylcarbodiimide as a coupling agent. This methodproduces yields of only 40- 50% of theoretical, whereas the othermethods set forth obtain much higher yields. The procedure is asfollows:

A solution containing 1 mole of the acid ester, 1 mole of thealkylamine, and 1.1 moles of dicyclohexylcarbodiimide was stirred atroom temperature for 20 hours. The precipitated crude substitutedamido-ester was filtered and recrystallized from hot chloroform. The hotsolution is also filtered to remove the insoluble urea formed as a sideproduct in this reaction.

Solvents which can be used for the recrystallization purification of thecrude amido-ester include methanol, ethanol, isopropanol, n-butanol,isobutanol, primary amyl alcohol, methyl amyl alcohol, 2-ethyl butanol,l-hexanol, 2-ethyl hexanol, 2,6-dimethyl-4-heptanol, isodecanol, 2,6,8-trimethyl-4-nonanol, undecanol, tetradecanol, heptadecanol, acetone,amyl acetate, ethyl acetate, chloroform, tetrahydrofuran and atetrahydrofuran-ethyl alcohol mixture.

Aromatic and aliphatic hydrocarbon solvents may also be used such as forexample xylene, mesitylene, p-cumene, ethyl benzene, pentane, hexane,octane, decane, dodecane.

These amido-esters are valuable as synthetic waxes and can be used forthe known intended uses of the natural waxes.

In summary the amide-esters are formed as follows:

0 Rr0( 3-Rz-i JOH acyl chloride forming reagent (acid ester) R1O-CRz-OC1(acyl chloride of corresponding acid ester) 0 Rs 0 R3R,-0(3-Rzii01+H-IQR. R 0iiR,iir I-R, (acyl chloride of eorre-(amido-ester synthetic wax) spending acid ester) Thus, the amido-estersynt'hetic waxes of the present invention have the general formula R OCi-Rz-( I I-R4 In this formula: R is an alkyl radical having from 16-22carbon atoms. Exemplary of the R alkyl radicals are n-hexadecyl,n-heptadecyl, n-octadecyl, n-nonadecyl, neicosyl, n-heneicosyl,n-docosyl, and the various positional isomer thereof, such as, forexample, t-hexadecyl, t-eicosyl, and iso-octadecyl.

R is an alkylene radical having from 2-8 carbon atoms. Exemplary of Ralkylene radicals are ethylene, propylene, butylene, pentylene,'hexylene, heptylene, octylene, and the various positional isomersthereof, such as, for example, iso-propylene, t-butylene, iso-pentylene,and iso-octylene.

R and R are selected from the group consisting of hydrogen and alkylradicals having from 1-22 carbon atoms. Exemplary of the R and R alkylradicals are methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl,n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl,n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, noctadecyl,n-nonadecyl, n-eicosyl, n-heneicosyl, n-docosyl (amine) and the variouspositional isomers thereof, such as isopropyl, iso-butyl, t-butyl,sec-butyl, iso-amyl, t-amyl, isohexyl, t-heptyl, iso-octyl,2-ethyl-hexyl, t-octyl, t-decyl, t-pentadecyl, t-nonadecyl, andt-dodecyl.

The following amido-ester synthetic waxes which are examples of theinvention, may be prepared by procedures similar to those outlined aboveand in the subsequent specific examples:

TABLE I II II O OH O OH

O 0 CH3 H O CaH7 w aaOO(CHg)@-CNCH5 The following specific examples ofthe preparation of the amido-ester synthetic waxes will be helpful to aclear understanding of the invention:

Example 1 .N-stearyl docosyl succinamate In a reaction flask containing1000 ml. of diethyl ether was suspended 370.64 g. (1 mole) ofmonodocosyl-succinate. The mixture was cooled to -10 C. in an icesaltbath. To this mixture was added. with stirring, 229.08 g. 1.1 moles) ofphosphorus pentachloride. After one hour the mixture was filtered andwashed with diethyl ether. The acyl chloride formed was addedimmediately to a solution containing 269.58 g. (1 mole) of stearyl aminein a 1000 ml. of chloroform and 111.30 g. (1.1 moles) of triethylamine.This mixture was stirred, while cooling to 10 C. in an ice-salt bath,for three hours. The product was filtered, dried and recrystallized fromhot chloroform. A white crystalline material having a melting point of-92 C. resulted. A yield of 78% was obtained.

Example 2.--0ctadecyl glutaramide A suspension of 384.7 g. (1.0 mole) ofmonooctadecyl glutarate in 1.5 liters of anhydrous diethyl ether wascooled to -10 C. in an ice-salt bath. To this mixture was added 226 g.(1.09 moles) of phosphorus pentachloride with stirring. After one hourthe mixture was filtered and washed with anhydrous diethyl ether. Theacyl chloride thus formed was immediately added to 2.5 liters of coldconcentrated ammonium hydroxide with stirring. The reaction was cooledto -l0 C. in an icesalt bath and stirred for two hours. After filteringand washing the precipitate with water, the product was dried in avacuum oven at 50 C. for 4 hours. Recrystallization from hot chloroformyielded 300 gms. (77.8%) of 7 a White crystalline material with amelting point of 98- 99 C.

Example 3.N-rliethyl docosyl succinamate To a solution of 500millimeters of diethyl amine in 500 millimeters of distilled water isslowly added the acyl chloride formed from 370.64 grams (1 mole) ofmonodocosyl succinate and 207.9 grams of phosphorus pentachloride. Themixture is cooled to -10 C. in an ice-salt bath and stirred for onehour. The precipitated product is then filtered and washed with water.After drying the crude product is recrystallized in benzene yielding340.6 grams (80%) of a white crystalline material having a melting pointof 80-8l C.

The following examples set forth in Table II illustrate the preparationof other amido-ester synthetic waxes. The acid ester in anhydrous ethylether is mixed with 207.9 grams of phosphorus pentachloride at 10 C. ineach example for approximately two hours to form the acyl chloride ofthe acid ester. The acyl chloride of the acid ester is then reacted withthe amine indicated to form the amido-ester synthethic wax set forth.

TABLE II Reactants Product Example Amide-ester syn- Acid ester (grams)Amine (grams) thetic wax (grams) 4 Monohexadecyl NH OH 1.5 liters.Hexadecyl succinsuccinate 342.6 amide 273.3 g. g. (1 mole). 5.Monodocosyl Methyl amine N-methyl docosyl glutarate 440.8 62.1 g. (2moles). glutaramate g. (1 mole). 317.7 g. 6. Monooctadecyl Diethyl amineN-diethyl octasuberate 426.8 146.3 g. (2 deeyl suberag. (1 mole).moles). mate 375 g. 7 Monoeicosyl su- Methyl butyl N-methyl N -l)utylberate 454.8 g. amine 174.3 g. eicosyl suber- (1 mole). (2 moles). amate386.4 g. 8 Monodocosyl seb- Docosyl amine N -docosyl docosyl acate 530.9g. 280.3 g. (1 sebacamate (1 mole). mole). 455.2 g. 9 MonohexadecylMethyl butyl N -rnethyl N-butyl succinate 342.6 amine 174.3 g. hexadecylsucg. (1 mole). (2 moles). cinamate 289.0 g. 10 Monoelcosyl seb- Methylamine N-methyl eicosyl acate 482.9 g. 62.1 g. (2 sebacamate (1 mole).moles). 297.4 g. 11 Monooctadecyl Docosyl amine N -docosyl octasuberate426.8 280.3 g. (1 decyl suberg. (1 mole). mo1e)+1.1 mole amate 315 g.

triethyl amine. 12 Monodocosyl Methyl ethyl N-methyl N-ethyl glutarate440.8 amine 118.26 g. docosyl glutarag. (1 mole). (2 moles). mate 331.5g. 13 Monohexadecyl I-Iexadecyl amine N-hexadecyl hexasuecinate 342.6208.19 g. (1 decyl succinag. (1 mole). mole). mate 368.9 g.

The amido-ester synthetic waxes of the present invention preparedaccording to the preceding examples are white crystalline solids, havinga melting point in the range 80'-130 C. The high sharp melting point,hardness, ductility, adhesiveness, compatibility, dispersing action forcarbon black, oil retention and retention of hardness when diluted withmineral oil which these synthetic waxes exhibit is the reason thesecompounds can be used for the same purposes for which the natural waxesof carnauba, ouricury, and montan are used. For example, these waxes maybe used in polishes (paste and liquid), carbon transfer inks, as moldlubricants, synthetic lubricants, etc.

The similarity in general steric aspect of the synthetic waxes to thenatural waxes is reflected in their hardness, high melting point,ductility, gloss and their compatibility with natural waxes and solventsfor said waxes.

Bi-dipolar compounds are generally harder and have higher melting pointsthan simple esters. When amido groups are attached to these bi-dipolarcompounds hardness and the melting points are even greater. This is dueto the ability of these compounds to display a large degree of hydrogenbonding.

Amides characteristically exhibit a high degree of hy- 8 drogen bonding.This hydrogen bonding results in higher melting and boiling points ofamides than their acid counterparts. Consequently, amido-esters havehigher melting points than the acid esters from which they are formed.

Equally important is that hydrogen bonding allows an orderly arrangementof the molecules. This orderly arrangement can result in a more compactand denser compound. The increased hardness of these amidoester waxes ascompared to the acid ester Waxes can be attributed to this compactnessof molecular arrangement.

The increased melting point and hardness of amidoester waxes make thesematerials useful in lubricants especially where high temperatures arerequired. Hardness in a Wax is desirable in polish formulations where ahard tough film is most desirable.

The amido-ester synthetic waxes of the present invention have thedesirable melting points which permit them to be incorporated in inkformulations which are used in the manufacture of carbon paper. Suchinks are of the hot melt type. This means that the inks are heated toapproximately 100 C. so that they become very fluid and can be coated ona paper backing. Drying is accomplished by allowing the ink to return tonormal temperature. Although several different carbon paper inkformulations are used they are all composed essentially of a wax, ahydrocarbon oil, a coloring substance, usually carbon blacks and/ortoner. Varying the ratios of these components allows the finalcharacteristics of the ink to be varied.

Conventional carbon paper inks usually contain a natural wax (forexample, carnauba wax) either as the sole wax component or blended withother waxes. The natural waxes, especially carnauba wax, give reallysatisfactory overall results in terms of coating ease, lack of smear,excessive tack and offsetting. After thoroughly dispersing the naturalwax (e.g. carnauba wax) with paraflin or mineral oil and carbon blackand heating, the composition attains a fluidity which enables it to beroller-coated on a paper base to produce an even, smooth uniformcoating. Upon hardening the inks show good retention of the oil and arerelatively free from smudging.

The new carbon transfer ink compositions produced according to thepresent invention duplicate very closely the properties and performanceof conventional ink compositions containing carnauba wax. In addition,the new ink compositions exhibit superior properties and performance ascompared with ink compositions containing ouricury and montan wax. It istheorized that this is the result of the duplication in the amido-estersynthetic Wax compounds of the bi-dipolarity, found in the esters whichmake up the major ingredient of natural waxes such as especiallycarnauba wax and ouricury and montan wax. The presence of the amidogroup further enhances the synthetic wax by increasing its hardness andmelting point by providing more chances for hydrogen bonding thusrendering the synethic wax more polar.

Accordingly, the novel carbon transfer ink compositions of the presentinvention comprise paraffin ink oils, carbon blacks and compounds of theclass described having the following general formula:

lll

Example 14 A basic ink formulation was prepared by adding 25.8 grams ofN-methyl docosyl succinamate to a five and one half ounce capacitystainless steel mill. 25.8 grams of paraffin ink oil were then added tothe mill and the mill was placed on a hot plate to melt the wax. The N-methyl docosyl succinamate begins to melt at about 83 84 C. After theN-methyl docosyl succinamate has been completely melted, 8.4 grams ofcarbon black and 3 grams of nigrosine oleate toner were added and theheating is continued. When the temperature reaches 100 C., hot steelballs are added and the mill is shaken vigorously for about minutes.During this time, the temperature in the mill drops to about 75 C. Theink is then transferred to a standard carbon paper coating machine andis coated on a standard carbon paper backing. After tests forprintability and wear, it was found that the novel carbon paper inkcomposition, comprising N- methyl docosyl succinamate as a substitutefor carnauba wax, compared favorably with inks containing the naturalwax.

Example An ink composition is prepared according to the steps outlinedin Example 14, except that 25.8 grams of docosyl glutaramate aresubstituted in the formulation for the N-methyl docosyl succinamate.

Example 16 An ink is prepared as in Example 14, except 25.8 grams ofN-methyl N-butyl docosyl succinamate are substituted for the N-methyldocosyl succinamate.

Example 17 An ink is prepared according to the method in Example 14,except that 25.8 grams of N-diethyl docosyl succinamate are substitutedfor the N-methyl docosyl succinamate.

Example 18 An ink composition is prepared according to the process inExample 14, except 25.8 grams of a 1:1 mixture of docosyl succinamideand N-ethyl docosyl succinamate are substituted for the N-methyl docosylsuccinamate.

The amido-ester synthetic waxes of the present invention or mixturesthereof may also be used in the formulation of magnetic transfer ribboninks in place of, or in addition to the natural wax ordinarily used.

Printability of the foregoing ink compositions as determined by thequality of a fifth carbon copy prepared with the formulated inks wasuniformly good in all cases tested.

The paraffin ink oils used in the above examples are available fromcommercial sources, such as the Gulf Oil Company. The exact compositionof the oils is not known, but they are generally identified aspolycyclic, high-boiling petroleum fractions that have been de-colorizedby activated fullers earth or bauxite.

The carbon blacks employed in the manufacture of carbon paper inks arewhat are generally defined as channel blacks. Channel blacks of the longflow variety are generally preferred for use in carbon papers and areavailable commercially under the following trade names, Kohinoor,Witcolith, Mogul, and Peerless.

Toners and other dispersing agents are frequently added to carbon paperink compositions to obtain desired properties. Toners are prepared byprecipitation of organic dyes onto the surface of carbon blacks.

The proportions of synthetic wax, oil and carbon black may be variedwithin fairly wide ranges according to the properties desired in thefinal ink coating. Generally, the basic ingredients in carbon transferink compositions of the present type may vary within the followingranges: synthetic Wax from 30% to 50% be weight of the composition,parafiin ink oil from 10% to 50%, and carbon blacks from about 2% to20%. Up to about of toners and other optional additives may also beincluded.

The amido-ester synthetic waxes of the present invention havesatisfactory melting points which enable them to be formulated into inksand coated by standard coating machines without important departure fromconventional practice. These synthetic waxes duplicate and in someinstances exhibit superior properties when the properties are comparedto the carnauba, ouricury and montan natural waxes for example, highermelting points, greater hardness, lack of smear, etc.

The amide-ester synthetic waxes of the present invention areparticularly useful as an ingredient for various polishing compounds dueto its high melting point, its freedom from tack and its ability to takea high polish. The synthetic Waxes produce a hard, lustrous film.

A typical polishing formulation in paste or suspension form using thesynthetic wax of the invention consists of a silicone, one or more waxesand a solvent. The silicone imparts clarity, ease of polishing, gloss,water repellence and durability to the polish. The waxes add their knownqualities (as set forth above) and combinations of waxes are used toprovide certain desirable characteristics which are not obtained from asingle wax.

The solvent serves as a vehicle for all of the other constituents and isdependent to some extent upon the particular surface to be treated.

A formulation for an automobile paste wax using the amido-estersynthetic wax would be as foll-ows Ingredient: Amount (parts by weight)N-stearyl docosyl succinamate 37 Parafiin Wax 24 Coal tar naphtha 139Phenylpolysiloxane 2 melt the N-stearyl docosyl succinamate, paraffinwax and the silicone together in a jacketed kettle at a temperature of9095 C., then add the coal tar naphtha, stirring the batch meanwhile.Continue heating until the waxes are completely dissolved in thenaphtha. Then cool the batch to the pouring temperature, which is aboutC.

The paste wax made with N-stear'yl docosyl succinamate is firm. It iseasily applied to the surface to be polished (e.g. an automobile) andeasily rubbed to a high gloss with a clean dry cloth. The surfacespolished with this paste wax are found to repel Water.

The above paste Wax can be used to impart a high luster to all kinds ofsmooth, painted metal surfaces, especially automobile bodies. However,its use is not to be limited to automobiles. It can be used onfurniture, stoves, refrigerators, etc.

The amido-ester synthetic waxes can also be used to fortify naturalwaxes such as carnauba, ouricury or montan when used in the abovesuggested applications.

While the invention has been particularly described with reference topreferred embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention.

What is claimed is:

1. The method of preparing carbon transfer inks of the hot melt type,wherein at least one amido-ester synthetic wax compound used as the Waxmedium of said inks is selected from the class of compounds having thefollowing general formula:

s R O( i-R2y)I lR4 Where R is an alkyl radical having from 16-22 carbonatoms, R is an alkylene radical having from 2-8 carbon atoms, wherein Rand R are selected from the group consisting of hydrogen and an alkylradical having from 1-22 carbon atoms comprising the steps of:

mixing at least one of said amido-ester synthetic wax compounds andparafiin oil in a suitable container; heating the mixture at atemperature sufiicient to melt the wax constituent;

mixing carbon blacks with the wax-oil mixture while continuing theheating; and

1 1 milling the hot mixture by adding heated steel balls and shakingvigorously until the ink mixture is homogeneous.

2. The method of preparing carbon transfer inks of the hot melt type,wherein at least one amido-ester synthetic Wax compound is used as thewax medium of said ink selected from the class of compounds having thefollowing general formula:

0 0 Rs R1O( JRZ -I T R4 where R is an alkyl radical having from 16-22carbon atoms, R is an alkylene radical having from 2-8 carbon atoms,wherein R and R are selected from the group consisting of hydrogen andan alkyl radical having from 1-22 carbon atoms comprising the steps of:

mixing from about 30% to 50% by Weight of at least one of saidamide-ester synthetic Wax compounds, and from about 10% to 50% by weightof parafiin oil in a suitable container;

heating the mixture at a temperature sufficient to melt the Waxconstituent;

mixing from about 2% to 20% by Weight of carbon 1.2 blacks with thewax-oil mixture While continuing the heating; and milling the hotmixture by adding heated steel balls and shaking vigorously until theink mixture is homogeneous.

References Cited by the Examiner UNITED STATES PATENTS 1,930,429 10/33Rutskoskie 117-361 2,402,559 6/46 Hatte et a1. 117-361 2,427,255 9/47Burrell et al. 106-287 2,546,328 3/51 Arabian et va1. 106-271 2,561,8167/51 Pabst et al. 106-10' 2,742,432 4/56 Messina 252-515 2,783,206 2/57Messina 252-515 2,890,124 6/59 Mange 106-23 2,890,125 6/59 Mange 106-233,071,479 1/63 Fulenwider 106-10 ALFRED L. LEAVITT, Primary Examiner.

MORRIS LIEBMAN, ALEXANDER H. BROD- MERKEL, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 214,282 October 26, 1965 Hansel L, McGee et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1, line 68, strike out "in place of the natural waxes usedtheerin and" and insert instead which can be synthesized from availablechemicals column 5, lines 10 to 12, for O O read CH (CH2)21-O-C-(CH2)-C-NH cH (cH zJ3- 2 ll 3 read 0 O I II Signed and sealed this 29th dayof November 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD BRENNER Attesting Officer Commissioner ofPatents

1. THE METHOD OF PREPARING CARBON TRANSFER INKS OF THE HOT MELT TYPE, WHEREIN AT LEAST ONE AMIDO-ESTER SYNTHETIC WAX COMPOUND USED AS THE WAX MEDIUM OF SAID INKS IS SELECTED FROM THE CLASS OF COMPOUNDS HAVING THE FOLLOWING GENERAL FORMULA: 